Meeting Abstract
Venom is present in a diverse array of life, and its associated delivery mechanisms have been described in arachnids, cephalopods, cnidarians, crustaceans, insects, reptiles, mammals, and fishes (cartilaginous and bony). While most animals use their venom offensively, bony and cartilaginous fishes tend to utilize venom defensively. We have looked in detail at structural and anatomical variations in spines and accompanying venom glands across a variety of selachimorph families (e.g., Centrophoridae, Squalidae, Etmopteridae, Dalatiidae, Heterodontidae, and Somniosidae). There is significant morphological variation present both between and within families. We document variation in the size and shape of dorsal spines and their associated venom glands. The morphology, connectivity, and evolution of elasmobranch spines is relatively understudied in the literature. By using anatomical and molecular data, we developed a hypothesis of the recurrent evolution and impact of dorsal spines, and likely venom, in cartilaginous fishes.
